Siftproof bag



/rl l BY mE/w@ March 28, 1944. A. J. STERLING SIFT-PROOF BAG FiledOCf..V 25, 1941 Patented Mar. 1944 SIFTPROOF BAG Albert il. Sterling,Brooklyn, N.. Y.: VSarah M. Sterling execntrix o! said Albert J.Sterling, de-

ceased Application October 25, 1941.; Serial No. 416,472

(Cl. 22B-62) 1 Claim.

invention relates to bags and has vparticu- 'in wn in the art assift-proof bags.

siti.

.An object of the invention is to provide a newl ,.fnetl'lod of making`sift-prooi closures for bags which is simpler than any prior method ofthe reference improvements in what are kind and whici'i is,nevertheless, more eifective "for the purpose intended than mostof them.

Yanother object is toprovide a sift-proof closure efficient closure andwhich is at the same time strong enough to withstand even severe abusein handling.

The improved method and the product involves the use only of materialforming a part of the bag proper instead of tapes, liller cords and soon in effecting the closure. Where stitched seams are used the newconstruction provides a reinforcement for the stitch to prevent thestitches from tearing through and in addition, the needle punctures madein doing the stitching are sealed from both sides to prevent finecontents from sifting out through the punctures.

The invention is applicable to bags of either single or the multi-walltype and may be used with equal facility for the bags of either type.

With the foregoing and other objects in view the invention comprises anovel method of maklng a sealed bag closure and a novel product; thatis, a sift-proof closure having new and valuable characteristics. Anillustrative embodiment of the sift-proof closure is illustrated in theaccompanying drawing and the method of making it as hereinafterdescribed in detail, with the novel features of both the product and themethod being set forth in the claim appended hereto.

In said drawing:

Fig. 1 ls a view of a bag to which one form of the invention is applied,the figure illustrating particularly the flap employed in making theclosure. Fig. 2 shows the bag with the flap folded over the bag mouth toclose the mouth and one side of a row of stitches through the iiap andthe bag walls at the mouth of the bag.

Fig. 3 is the same as Fig. 2, but shows the opposite side of thestitched seam. I

Figs. 4, 5 and 6 illustrate successive steps in completing the sealedclosure. l

Fig. 7 is the same as Fig. 6, except that the former illustrates theinvention applied to a multi-wall bag.`

'Ihe invention is shown in the drawing as it would appear when appliedto a gussetedbag. Extending from and preferably integral with one wallof the bag is a long flap Ill. This ilap is long enough to provide threesections for the purpose hereinafter set forth. It is shown in thefigures as havingfold or crease lines li, but this is partly tosimplifythe explanation.

` While such fold or craselines l maylbe used fnl fil

they are not absolutely essential.

After the bag has been illled adhesive is ap plied either to the upperpart I2 Aof the bag Wall or to the portion I3 of the flap, orto both;and the flap is then drawn tightly over the mouth of the bag, asillustrated in Fig. 2. The adhesive will hold the flap and the bag wallin that position. In some instances it maypot be necessary to useadhesive on the surfaces I2 and I3, but that procedure is preferred.

After the flap has been drawn over the mouth of the bag it is stitchedthrough the flap and through the walls of the bag. Any form of stitch onthe single thread side.

may be employed which is strong enough and otherwise adapted to thepurpose. In the drawing,y the stitch is shown as a loop stitch; that is,a stitch having a series of loops I4 along one side of the seam, withthe loops being connected as illustrated. The bight of one loop passesaround the base of the next loop so that the loops not only give areinforcing for the stitch ing along one side but the connection betweenthe loops affords a preventive against sifting of the contents throughthe needle punctures. The other side of the seam has only a. singlethread as shown at I5 and if a seam tears when such a loop stitch isused the tear usually begins The seam is prefer--` ably sewed in such away that the single thread side of the seam is on the side whichincludes the portion' I3 of the flap. This gives extra bag .material onthe Weak side of the seam so as to reinforce the seam along that side.

After the stitching is completed, adhesive is applied and the remainderof the ilap folded back over the portion I3 and top of the bag and downover the other side so as to cover the loops Il. The adhesive may beapplied to the portions of the preliminary closure which includes thesides Il and I5 of the stitched seam and the flap then further folded asdescribed, but itis preferred to apply the adhesive to the portions I6and I1 of the nap before the flap is folded to final position. It isadvisable to use plenty of a good strong adv heslve and in some cases itmay be advisable tc. apply adhesive to all of the surfaces which will bebrought into contact by the final fold so that there will be a doubleamount of adhesive included in the nal fold. l

As shown in Fig. 4 in making this iinal fold the flap is turned up sothat the portion I6 is folded on a line I8 below the single threads I5of the stitched seam and then, as illustrated in Figs. 5 and 6, theremainder of the iiap is brought down over the loop side Il of thestitch. Sealing pressure may then be applied wherever it is thoughtto berequired.

The adhesive may be any of the usual glues, although for some uses itmay be advisable to use plioiilm or similar material which is softenedby heat and simultaneously pressed to effect a sealing operation.

The final closure oi a single wall bag is shown in cross-section in Fig.6. Als will there be seen, the stitch is' reinforced by an extrathickness of the paper on the weak side of the seam and the stitches arecovered from both sides by the flap. Adhesive between the contactingparts of the nap and the bag walls and between the contacting parts ofthe iiap after it is folded vholds all of the material in its intendedposition and also affords a very effective seal of the needle puncturesagainst sifting through the punctures of the bag contents.

The multi-wall construction is illustrated in Fig. 1. It is, except forthe number of plies, the same in every substantial respect as the singleply structure.-

From all of the foregoing it is clear that there is provided a veryeilicient and simple sift-proof closure and that in its making there isa new process or method involved which is in itself a very simple one.One advantage of the method is that it can readily be carried out bysimple automatic machinery and with a very considerable saving inmaterial and time of operators.

While an embodiment of the new closure and a preferred method of makingit have been described somewhat in detail, it is apparent that changesor variations might be made and it is not the desire to be limited byanything hereinabove contained, except to the extent indicated in theclaim which follows.

What is claimed is:

A paper bag having a sift-proof closure for its mouth comprising a flap,which is at least as wide as the mouth of the bag, extending from v andintegral with the bag wall at one side of the mouth, said flap havingtransversely 'extending fold lines defining three panels arranged to befolded over the mouth of said bag and reversely upon themselves alongone of the fold lines, stitching extending entirely across the mouth ofthe bag and comprising stitches extending through the bag walls' and thepanel adjacent thereto, and adhesive on the inner side of said stitchedpanel and on the inner side of the remaining two panels, said adhesivecovering the entire inner face of each of said panels and being in anamount on the inner face of each outer panel to completely cover andseal the holes produced by said stitches.

ALBERT J. STERLING

